Microsoft will allow existing Windows 7 and Windows 8/8.1 users upgrading to its Windows 10 platform - via the free upgrade offer launching on 29 July - perform a clean installation of Windows 10 at any time in the future on their device.

Microsoft has sent out notifications to Windows 7 and 8/8.1 users to reserve a copy of their Windows 10 free upgrade. Users can check the notification area on their devices to access the new Windows 10 upgrade notification.

Meanwhile, Engineering General Manager for Microsoft's Operating Systems Group, Gabriel Aul, confirmed via Twitter that those who prefer to perform a fresh install of Windows 10 instead of working with an upgraded version can do so at any point, once they have received a license via the free upgrade initiative.

Aul also stated that Windows 8.1 users will not have to use the Windows 8.1 product key for reactivating the Windows 10 upgrade.

Those who wish to perform a clean installation of Windows 10, can do so either via the built-in OS or with the downloadable ISO image that also lets users re-install Windows 10 - at no additional cost.

Windows 10 will incorporate a brand new mini start menu, which would be a major feature of Microsoft's unified platform. The OS will be released in 7 different editions catering to both general and enterprise users across the globe.